Organic compound and organic photoelectric element containing same
阅读说明：本技术 一种有机化合物和含其的有机光电元件 (Organic compound and organic photoelectric element containing same ) 是由 王子兴 王朋超 廖张程 吴空物 张迪 于 2021-06-09 设计创作，主要内容包括：本发明属于有机光电领域,具体涉一种有机化合物及包含其的有机光电元件,特别是有机电致发光二极管,其中有机化合物的结构如式(I)所示：式(I)代表的有机化合物群组具有一个显著的特征是它们的单线态能级S1与三线态能级T1的差值≤0.35电子伏特,详细说明信息及其有机光电元件可通过参照本文中提供的具体描述进行理解。本发明的有机化合物具有热活化延迟荧光特性,应用于有机电致发光二极管中,可提升三线态激子的利用效率,具体为使本发明的化合物作为发光元件功能层,可以使发光元件的电流效率提升,驱动电压降低,使用寿命明显延长,具有很好的商业化前景。(The invention belongs to the field of organic photoelectricity, and particularly relates to an organic compound and an organic photoelectric element comprising the same, in particular to an organic electroluminescent diode, wherein the structure of the organic compound is shown as the formula (I): the group of organic compounds represented by formula (I) has a remarkable feature that their singlet energy level S1 differs from the triplet energy level T1 by ≦ 0.35 electron volts, and the detailed information and organic optoelectronic elements thereof may be understood by referring to the detailed description provided herein. The organic compound has the characteristic of thermal activation delayed fluorescence, can improve the utilization efficiency of triplet excitons when being applied to an organic electroluminescent diode, and particularly can improve the current efficiency of a light-emitting element, reduce the driving voltage and obviously prolong the service life when being used as a functional layer of the light-emitting element, thereby having good commercial prospect.)
1. An organic compound having the structure of formula (I):
wherein X1 to X3 are independently selected from N or C-R4, and at least two are N; the ring CY1 is an aromatic condensed ring or an aromatic hetero-condensed ring of C7-C30, Ar1 and Ar2 are independently selected from substituted or unsubstituted aryl of C6-C60 and substituted or unsubstituted heteroaryl of C1-C60; r1 to R5 are each independently selected from hydrogen, deuterium, CN, halogen, substituted or unsubstituted C1 to C60 alkyl, substituted or unsubstituted C2 to C60 alkenyl, substituted or unsubstituted C1 to C60 alkoxy, substituted or unsubstituted C1 to C60 cycloalkyl, substituted or unsubstituted C1 to C60 heteroalkyl, substituted or unsubstituted C6 to C60 aryl, substituted or unsubstituted C1 to C60 heteroaryl, substituted or unsubstituted C1 to C60 amine, substituted or unsubstituted C1 to C60 silicon group, substituted or unsubstituted C6 to C60 aromatic fused ring, substituted or unsubstituted C1 to C60 heteroaromatic fused ring; ar1, Ar2, R1 through R5 each independently may be partially or fully deuterated, each independently may be partially or perfluorinated; r1 to R5 may be unsubstituted or polysubstituted according to valence bond rules; adjacent R1 to R5 may form a ring, n is independently an integer of 0 to 8; and the difference between the singlet state energy level S1 and the triplet state energy level T1 of the organic compound is less than or equal to 0.35 electron volt.
2. The organic compound of claim 1, wherein ring CY1 in formula (I) is independently selected from one of formula (a) to formula (H):
wherein Y is independently selected from O, S, N-R7, CR7R7, SiR7R7 and B-R7, and Z is independently N or C-R; r5 to R7 are each independently selected from hydrogen, deuterium, CN, halogen, substituted or unsubstituted C1 to C60 alkyl, substituted or unsubstituted C2 to C60 alkenyl, substituted or unsubstituted C1 to C60 alkoxy, substituted or unsubstituted C1 to C60 cycloalkyl, substituted or unsubstituted C1 to C60 heteroalkyl, substituted or unsubstituted C6 to C60 aryl, substituted or unsubstituted C1 to C60 heteroaryl, substituted or unsubstituted C1 to C60 amine, substituted or unsubstituted C1 to C60 silicon group, substituted or unsubstituted C6 to C60 aromatic fused ring, substituted or unsubstituted C1 to C60 heteroaromatic fused ring; when two or more adjacent R5 to R7 may form a ring with each other; n is independently an integer from 0 to 8; m is 1 or 2; indicates the position of the linkage to N or C.
3. An organic compound according to claim 1 or 2, wherein ring CY1 in formula (I) is independently selected from one of the following representative structural formulae:
wherein R8 is independently selected from CN, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C1-C60 cycloalkyl, substituted or unsubstituted C1-C60 heteroalkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C1-C60 heteroaryl, substituted or unsubstituted C1-C60 amine, substituted or unsubstituted C1-C60 silicon, substituted or unsubstituted C6-C60 aromatic fused ring and substituted or unsubstituted C1-C60 heteroaromatic fused ring; y, Z, R6, R7 and n are as defined in claim 2.
4. The organic compound according to claim 1 or 2, wherein the structural formula of formula (I) is independently selected from one of the following representative structures:
wherein Y, Z, R8 is as defined in claim 3, and X1 to X3, R1 to R7, Ar1, Ar2, n are as defined in claim 1.
5. An organic compound according to any one of claims 1 to 4, wherein R1 to R7 in the above structure are independently selected from one of hydrogen, deuterium, halogen, CN, or R1 to R8 are independently selected from one or more combinations of the following substituents:
6. the organic compound according to claim 1 or 2, wherein the formula of the organic compound is independently selected from one of the following representative structures:
7. a preparation comprising the organic compound according to any one of claims 1 to 6 and at least one solvent, wherein the solvent used is not particularly limited, and there can be used an unsaturated hydrocarbon solvent such as toluene, xylene, mesitylene, tetrahydronaphthalene, decahydronaphthalene, bicyclohexyl, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, etc., a halogenated saturated hydrocarbon solvent such as carbon tetrachloride, chloroform, dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, etc., a halogenated unsaturated hydrocarbon solvent such as chlorobenzene, dichlorobenzene, trichlorobenzene, etc., an ether solvent such as tetrahydrofuran, tetrahydropyran, etc., an ester solvent such as alkyl benzoate, etc., which are well known to those skilled in the art.
8. An organic light-emitting element, comprising:
a first electrode;
a second electrode facing the first electrode;
the organic functional layer is clamped between the first electrode and the second electrode;
wherein the organic functional layer comprises an organic compound according to any one of claims 1 to 6.
9. An organic light-emitting element comprising a cathode layer, an anode layer and an organic functional layer comprising at least one of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer and an electron injection layer, wherein any one of the layers of the element contains the organic compound according to any one of claims 1 to 6.
10. The organic light-emitting element according to claim 8 or 9, wherein the light-emitting layer contains the organic compound according to any one of claims 1 to 6 and a corresponding guest material, wherein the guest material is present in an amount of 1 to 50% by mass, and the guest material is not limited and may be a fluorescent material or a phosphorescent material.
11. The organic light-emitting element according to claim 8 or 9, wherein the light-emitting layer contains the organic compound according to any one of claims 1 to 6 as a light-emitting sensitizer in a ternary combination of a host material and a guest material, and the organic compound is contained in an amount of 0.5 to 50% by mass.
12. The organic light-emitting element according to claim 8 or 9, wherein the electron transport layer contains the organic compound according to any one of claims 1 to 6 and an n-type dopant, the n-type dopant is not particularly limited, and the organic compound is contained in an amount of 0.5 to 70% by mass.
13. A display or lighting device comprising the organic light-emitting element according to any one of claims 8 to 12.
Technical Field
The invention belongs to the field of organic photoelectricity, and particularly relates to an organic compound and an organic photoelectric element comprising the same, in particular to an organic electroluminescent diode.
Background
The organic electroluminescent device (OLED) has the advantages of wide viewing angle, high response speed, high color quality, capability of realizing flexible light emission and the like, and has wide application prospect. An organic electroluminescent device with high efficiency and long lifetime is generally the result of an optimized match of the device structure with various organic materials. Common OLED devices typically comprise the following classes of organic materials: hole injection materials, hole transport materials, electron transport materials, and light emitting materials (dyes or doped guest materials) and corresponding host materials of each color. Although the research on organic electroluminescence is rapidly progressing, there are still many problems to be solved, such as improvement of efficiency and design and synthesis of new materials with higher color purity; designing and synthesizing host-guest materials with high efficiency triplet exciton utilization rate. For the organic electroluminescent device, the luminous quantum efficiency of the device is the comprehensive reflection of various factors and is an important index for measuring the quality of the device. Therefore, it is important to design and develop a host material with high triplet exciton utilization rate.
The present invention provides an organic compound that connects donor and acceptor groups through an aromatic or heteroaromatic ring, making the transfer of electrons and holes more balanced; the molecule has proper triplet state energy level and thermal activation delayed fluorescence characteristic, namely the difference value of the singlet state energy level S1 and the triplet state energy level T1 of the organic compound is less than or equal to 0.35 electron volt, the utilization rate of triplet state exciton energy in a luminescent device can be improved, and the specific expression is that the efficiency of a device constructed by using the organic compound is improved, the voltage is reduced, and the service life is prolonged.
Disclosure of Invention
The invention provides an organic compound, the structural formula of which is shown as the formula (I):
wherein X1 to X3 are independently selected from N or C-R4, and at least two are N; the ring CY1 is an aromatic condensed ring or an aromatic hetero-condensed ring of C7-C30, Ar1 and Ar2 are independently selected from substituted or unsubstituted aryl of C6-C60 and substituted or unsubstituted heteroaryl of C1-C60; r1 to R5 are each independently selected from hydrogen, deuterium, CN, halogen, substituted or unsubstituted C1 to C60 alkyl, substituted or unsubstituted C2 to C60 alkenyl, substituted or unsubstituted C1 to C60 alkoxy, substituted or unsubstituted C1 to C60 cycloalkyl, substituted or unsubstituted C1 to C60 heteroalkyl, substituted or unsubstituted C6 to C60 aryl, substituted or unsubstituted C1 to C60 heteroaryl, substituted or unsubstituted C1 to C60 amine, substituted or unsubstituted C1 to C60 silicon group, substituted or unsubstituted C6 to C60 aromatic fused ring, substituted or unsubstituted C1 to C60 heteroaromatic fused ring; ar1, Ar2, R1 through R4 each independently may be partially or fully deuterated, each independently may be partially or perfluorinated; r1 to R5 may be unsubstituted or polysubstituted according to valence bond rules; adjacent R1 to R5 may form a ring, n is independently an integer of 0 to 8; and the difference between the singlet state energy level S1 and the triplet state energy level T1 of the organic compound is less than or equal to 0.35 electron volt.
Preferably, ring CY1 in structural formula (I) is independently selected from one of formula (a) to formula (H), but does not represent that the present invention is limited to the following structures:
wherein Y is independently selected from O, S, N-R7, CR7R7, SiR7R7 and B-R7, and Z is independently N or C-R; r5 to R7 are each independently selected from hydrogen, deuterium, CN, halogen, substituted or unsubstituted C1 to C60 alkyl, substituted or unsubstituted C2 to C60 alkenyl, substituted or unsubstituted C1 to C60 alkoxy, substituted or unsubstituted C1 to C60 cycloalkyl, substituted or unsubstituted C1 to C60 heteroalkyl, substituted or unsubstituted C6 to C60 aryl, substituted or unsubstituted C1 to C60 heteroaryl, substituted or unsubstituted C1 to C60 amine, substituted or unsubstituted C1 to C60 silicon group, substituted or unsubstituted C6 to C60 aromatic fused ring, substituted or unsubstituted C1 to C60 heteroaromatic fused ring; when two or more adjacent R5 to R7 may form a ring with each other; n is independently an integer from 0 to 8; m is 1 or 2; indicates the position of the linkage to N or C.
More preferably, ring CY1 in formula (I) is independently selected from one of the following representative structural formulae, but does not represent that the present invention is limited to the following structure:
wherein R8 is independently selected from CN, substituted or unsubstituted C1-C60 alkyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C1-C60 cycloalkyl, substituted or unsubstituted C1-C60 heteroalkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C1-C60 heteroaryl, substituted or unsubstituted C1-C60 amine, substituted or unsubstituted C1-C60 silicon, substituted or unsubstituted C6-C60 aromatic fused ring and substituted or unsubstituted C1-C60 heteroaromatic fused ring; y, Z, R6, R7 and n are as defined above.
In connection with the above description of CY1, preferably, the compound represented by formula (I) is independently selected from one of the following representative structures, but does not represent that the present invention is limited to the following structure:
wherein, Y, Z, R8; x1 to X3, R1 to R7, Ar1, Ar2, n are the same as defined above.
Preferably, in the structural formula described above, R1 to R8 are independently selected from hydrogen, deuterium, halogen, CN, and may also be independently selected from one or more combinations of the following groups, but do not represent that the present invention is limited to the following groups:
according to the above description, it is particularly preferred that an organic compound according to the present invention is selected from one of the following representative structural formulae, but does not represent that the present invention is limited to the following structure:
the present invention also claims a preparation comprising the compound of formula (I) and one or more solvents, wherein the solvent used is not particularly limited, and unsaturated hydrocarbon solvents such as toluene, xylene, mesitylene, tetrahydronaphthalene, decahydronaphthalene, bicyclohexyl, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, carbon tetrachloride, chloroform, dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, etc., halogenated unsaturated hydrocarbon solvents such as chlorobenzene, dichlorobenzene, trichlorobenzene, etc., ether solvents such as tetrahydrofuran, tetrahydropyran, etc., ester solvents such as alkyl benzoate, etc., which are well known to those skilled in the art can be used.
The present invention claims an organic light-emitting element,
the method comprises the following steps: a first electrode;
a second electrode facing the first electrode;
the organic functional layer is clamped between the first electrode and the second electrode;
wherein the organic functional layer comprises the organic compound.
The present invention preferably protects an organic light emitting element comprising a cathode layer, an anode layer and an organic layer comprising at least one of a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron injection layer, an electron transport layer, wherein the light emitting layer of the device contains the organic compound.
The organic light-emitting element light-emitting layer contains the organic compound and a corresponding guest material, the guest material is not particularly limited, the mass percentage of the guest material is 1-50%, and the guest material is not limited at all and can be a fluorescent material or a phosphorescent material.
The invention also claims an organic light-emitting element, wherein a light-emitting layer of the light-emitting element contains the organic compound as a light-emitting sensitizer and a ternary combination formed by a host material and a guest material, wherein the mass percent of the organic compound is 0.5-50%; there is no particular requirement for the ratio between a host and guest material.
The organic compound can also form electron transmission together with a metal complex, and is applied to an organic light-emitting element, the metal complex is not particularly limited, and the mass percent of the organic compound is 0.5-70%.
In the present invention, the organic light-emitting element is an anode which can be formed by depositing metal, an oxide having conductivity, or an alloy thereof on a substrate by a sputtering method, electron beam evaporation, vacuum deposition, or the like; and sequentially evaporating a hole injection layer, a hole transport layer, a luminescent layer, a hole blocking layer and an electron transport layer on the surface of the prepared anode, and then evaporating a cathode. The organic light emitting element of the present invention can be classified into top emission, low emission, or double-sided emission.
The organic light-emitting element of the present invention is suitable for use in various electronic products that constitute display and lighting requirements.
The invention relates to an organic compound, which is characterized in that the difference (delta) between the singlet state energy level S1 and the triplet state energy level T1 of the organic compound is improvedST) Delta of the organic compounds of the invention can be adjusted by introducing a special ring CY1STLess than or equal to 0.35 electron volt. The organic compound has high luminous efficiency, can generate heat delay fluorescence, and obviously improves the energy transmission between a host and an object and the utilization efficiency of triplet excitons in an organic light-emitting device; specifically, the organic compound is used as a functional layer, especially used as a host material in a light-emitting layer and matched with a proper red light guest material, and the organic compound is similar to the host material in the light-emitting layer>Compared with the compound with 0.37 electron volt, the prepared organic light-emitting device has the advantages that the current efficiency is improved, the operating voltage is properly reduced, the service life of the organic light-emitting element is prolonged, and an innovative thought is provided.
Drawings
FIG. 1 is a structural diagram of an organic electroluminescent diode device according to the present invention.
Where 110 denotes a substrate, 120 denotes an anode, 130 denotes a hole injection layer, 140 denotes a hole transport layer, 150 denotes a light emitting layer or an active layer, 160 denotes a hole blocking layer, 170 denotes an electron transport layer, 180 denotes an electron injection layer, and 190 denotes a cathode.
FIG. 2 is a graph showing transient fluorescence spectra of the compound N-15 of the present invention and the comparative compound RH-2.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In a preferred embodiment of the present invention, the OLED device according to the invention comprises a hole transport layer, which may preferably be selected from known or unknown materials, particularly preferably from the following structures, without representing the present invention being limited to the following structures:
in a preferred embodiment of the present invention, the hole transport layer contained in the OLED device of the present invention comprises one or more p-type dopants. Preferred p-type dopants of the present invention are, but do not represent a limitation of the present invention to:
in a preferred embodiment of the present invention, the electron transport layer may be selected from at least one of the compounds ET-1 to ET-13, but does not represent that the present invention is limited to the following structures:
the electron transport layer may be formed from an organic material in combination with one or more n-type dopants (e.g., LiQ).
The innovation of the invention is illustrated by the following representative chemical structural formula:
comparison of the HOMO, LUMO, triplet energy level, Delta of Compounds RH-1 to RH-6 with the representative Compounds of the invention N-07 to N-19-5STListed in table 1:
TABLE 1
The following intermediates were obtained by third party customization:
according to the existing literature and the related technical reserves, the general synthesis procedure of the organic compounds of the invention is as follows:
general synthesis steps: intermediate 1(10 mmol), intermediate 2(10 mmol), KOH (30 mmol), DMF (120 ml) were heated to 130 ℃ under nitrogen atmosphere and reacted for 24 hours. After the reaction is finished, pouring the mixture into ice water, filtering, washing a solid crude product by using ice water and cold methanol, and drying. Purifying the mixture by a silica gel column through dichloromethane/methanol (100: 1-10: 1) to obtain the target organic compound, wherein the yield and the mass spectrum identification result of the compound are as follows:
compound (I)
Intermediates
Yield of
Actual measurement MS
Theoretical MS
N-07
IN-07
67％
748.3
748.26
N-09
IN-09
75％
698.2
698.25
N-11
IN-11
78％
724.3
724.26
N-13
IN-13
81％
800.3
800.29
N-15
IN-15
81％
774.3
774.28
N-16
IN-16
82％
774.3
774.28
N-17
IN-17
78％
814.3
814.27
N-18
IN-18
65％
830.3
830.25
N-110
IN-110
86％
840.3
840.33
N-115
IN-115
80％
814.3
814.27
N-118
IN-118
77％
856.3
856.30
N-119
IN-119
76％
840.3
840.33
N-120
IN-120
75％
814.3
814.27
N-11-2
IN-11-2
79％
724.2
724.26
N-13-2
IN-13-2
78％
800.3
800.29
N-15-2
IN-15-2
87％
774.3
774.28
N-16-2
IN-16-2
83％
774.3
774.28
N-17-2
IN-17-2
86％
814.3
814.27
N-18-2
IN-18-2
74％
830.3
830.25
N-110-2
IN-110-2
84％
840.3
840.33
N-111-2
IN-111-2
78％
814.3
814.27
N-118-2
IN-118-2
83％
856.3
856.30
N-11-3
IN-11-3
79％
724.3
724.26
N-14-3
IN-14-3
74％
800.3
800.29
N-15-3
IN-15-3
72％
774.3
774.28
N-16-3
IN-16-3
71％
774.3
774.28
N-17-3
IN-17-3
76％
814.3
814.27
N-18-3
IN-18-3
69％
830.2
830.25
N-110-3
IN-110-3
74％
840.3
840.33
N-111-3
IN-111-3
77％
814.3
814.27
N-11-4
IN-11-4
84％
724.3
724.26
N-15-4
IN-15-4
81％
774.3
774.28
N-16-4
IN-16-4
80％
774.3
774.28
N-18-4
IN-18-4
80％
830.3
830.25
N-11-5
IN-11-5
67％
715.2
715.24
N-12-5
IN-12-5
71％
715.2
715.24
N-13-5
IN-13-5
72％
715.2
715.24
N-14-5
IN-14-5
71％
715.2
715.24
N-15-5
IN-15-5
65％
715.2
715.24
N-16-5
IN-16-5
75％
765.2
765.25
OLED device examples:
the structure of the top-emitting OLED device is implemented specifically in such a way that a hole injection layer is HT-1: P-3(95:5 v/v%) and the thickness is 10 nanometers on ITO/Ag/ITO-containing glass; the hole transport layer is HT-1 and has a thickness of 100 nm; the electron blocking layer is HT-8 with a thickness of 10 nm, the light emitting layer is [ RH-1 or RH-2 or the organic compound of the invention ]: RD-1(97:2 v/v%) with a thickness of 35 nm, and the electron transport layer is ET-13: LiQ (50:50 v/v%) with a thickness of 35 nm, then evaporating a cathode Yb of 1 nm, an Ag of 14 nm and an evaporated CPL layer of 70 nm.
According to the above device embodiments, the characteristics of current efficiency, operating voltage, lifetime, etc. of OLED devices having different light emitting layers are summarized in table 2.
TABLE 2
From Table 1, the comparative compounds RH-1 to RH-6 have very close HOMO levels between-5.40 and-5.60 eV, LUMO levels between-2.80 and-3.10 eV, and their triplet levels are also relatively close, all between 2.30 and 2.40 eV, to the preferred compounds of the present invention. However, the difference Δ of the singlet energy level S1 and the triplet energy level T1 for the comparative compounds RH-1 to RH-6 was comparedSTAt 0.41 to 0.47 electron volts. The inventors have unexpectedly found that after replacing phenyl, naphthyl or fluorene etc. linked in RH-1 to RH-6 with the ring CY1 of the present invention [ represents a compound (Table 1)]Find their ΔSTCan be reduced to below 0.35 electron volts. FIG. 2 shows the reduction ΔSTThereafter, the representative compound of the present invention, N-15, produced significant thermally activated delayed fluorescence. According to the existing luminescence theory, the Delta of most organic compounds in the inventionSTCompounds below 0.35 electron volts, which may also produce thermally activated delayed fluorescence. Using them as host for red light guest material RD-1Device examples 1 to 21 were prepared and the device performance results are shown in table 2.
From table 2, the driving voltage of the preferred devices 1 to 21 is reduced as compared with the comparative device 1-2, but the light emitting efficiency is improved significantly and the lifetime of the device is prolonged. Device example 3 used N-11 as the main component and comparative device 2 used RH-2 as the main component, and it was found that N-11 only has 1 more benzene ring than RH-2, and the current efficiency of device example 3 reached 52.7cd/a, which is 129% of that of comparative device 2, and the lifetime of the device increased by 106 hours (55%). In particular, the current efficiency of device example 10 reached 135% of that of comparative device 2, the lifetime of the device was increased by 60%, and the operating voltage was reduced by 0.3 volts.
Delta of organic Compounds N-07 and N-09 of the present inventionSTAt 0.34eV, the current efficiencies of device examples 1 and 2 using them as the host were 50.3 and 51.2cd/A, as a function of ΔSTThe device effect of other organic compounds in the invention is obviously improved. The results in tables 1 and 2 fully show that the compounds of the present invention have the characteristics of thermally activated delayed fluorescence, and when they are used as hosts of red light objects to construct the light emitting layer of an organic light emitting device, the energy transmission between the hosts and the objects can be significantly improved, so that the operating voltage of the device is reduced, and the efficiency and the lifetime of the device are improved.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.